Silo network security codes is a keycard in the Fallout: New Vegas add-on Lonesome Road.
Location
It can be found in Base Commander Martin Retslaf's desk in an office on the second floor of the Hopeville missile silo.
Transcript
|======================|
|MINUTEMAN XI - CONSTANTINE|
|LAUNCH PROTOCOL 10.77 |
|SECURITY CLEARANCE ALPHA |
|======================|
|EAM CLEARANCE: G 5 S S 1 8|
|* * >> USAF DEFCON |
|* * >> EXEC:'BAGMAN' |
|======================|
|AUTH CODE: 0000000000 |
|======================|
|RESPONSE SCENARIO MX-CN91 |
|ICBM RESPONSE/NUCLEAR |
|BASE COMMAND EYES ONLY |
|======================|
Behind the scenes
The transcript for this note is exactly the same as the transcript for the Fort Constantine launch codes appearing in Fallout 3, and as a result mentions Fort Constantine rather than the Hopeville Ballistic Defense Station.
